Mixture of polychloroprene, vinyl chloride-acrylonitrile copolymer, and butadiene-acrylonitrile copolymer



Patented Nov. 3, 1953 MIXTURE OF POLYCHLGROPRENE, CHL'GR'I DE-AORYLONITRIDE C ORQLYMER,

BUT-ADIENE ACRYLQNIT-RILE 10.0-

POLYMER RalphJ. Signer, Chicago, andKeith F. Beal, Park Forest, "111., assignors to The Visking Corporation, Chicago, 111., a corporation of Virginia No Drawing. Original application January 51.4,

1941, Serial N0. 122,082. Divided and this applicationJunefi, .1950, Serial No. 166,972

8 Claims. 1

This invention, which is ,a division of copending application Ser. No. 7222082, filed January '14, 1947 "now U. '8. Patent No. 2,547,605, relates to resinous compositions and formed structures produced therefrom. More particularly, it relates to a new and "improved synthetic resin composition and formed structures produced therefrom.

Many synthetic resins, such as, for example, vinylidene chloride-acrylonitrile copolymer, vinylidene chloride-vinyl chloride copolymer, polycliloroprene, l;3 butadiene-acrylonitrile copoly- 'mer, vinyl chloride-vinyl acetate copolymer, vinyl chlorid'e-eacrylonitrile copolymer, polyvinylidene chloride, etc. are currently and commercially available. A film produced mm any of the aforementioned synthetic resins does not possess the necessary properties of flexibility, high resistance to tear, high elongation, capacity to return after elongation, high tensile strength, high resistance to moisture vapor penetration and'to penetration by gases, as are required for the packagingof foodstuffs. Attempts were made to improve the physical properties of such films by the incorporation of aliquid plasticizer in the composition from which the films are produced. 'Howeven'films containing a liquid plasticizer are unsatisfactory :for the reason that such liquid plasticizers migrate from the resin or disappear by evaporation, leaving :the resin embrittled, and frequently contaminate the contents of thepackage especially if the contents of the package is a-foodstufi.

In the course of research to improve the ,properties of films produced from synthetic resins mentioned, attempts "were made to prepare "films of resinous compositions containing a plurality 'of synthetic resins. However, when attempts were made to form "a resinous composition of p'olychloroprene with vinylidene chloride-acrylonitrile copolymer, "it was found that such resins were incompatible or incompatible in proportions "which "are necessary to give the desired results.

An object of this invention is to make a plurality of resins, which are normally incompatible in desired "proportions, compatible.

Another object of this invention is to provide "a resinous composition containing aplurality of resins normally incompatiblerm the desiredproportions and 'a blending agent which Will make suchresins compatible.

An additional object of this invention is to provide formed structures formed of normally incompatible resins but which are compatible :in the's'tructure.

A further-object of this invention is to provide resinous formed structures having improved physical'properties.

2 A specific-object of this invention is to provide films formed of resinous compositions having physical properties which render them suitable for us as a packaging material.

Other :and additional objects will become la ;Darent hereinafter.

The above objects are accomplished, in genal, by n rp r tin in a r sinous c mposit on, containing ,a plurality .of synthetic resins nroportions at which such resins are norma ly .incompatible but which are necessary to obtain the desired properties, a blending agent whereby a homogeneous resinous composition is -.obtained from which the desired ,formed structure is prepared and in which structure thessynthetic resins are compatible.

The blending agent, in general, .a synthetic resin as will hereinafter the more iullyqexplained.

:Usually, the synthetic :resin components and the blending agent are dissolved in a solvent :01 solvent mixture Wherebya homogeneous solution is obtained. Herein the term solvent covers a single solvent or a solvent mixture. No precise sequence for dissolving the resins and blending agent in the solvent .is required. "lfhe resin components-and blendin a ent can beacldcd separately or simultaneously to the solvent. After the desired solution ,has been prepared, it is ,p,rocessed depending on the desired formed structure. In one embodiment of theinvention, the resinous composition is formed into the desired formed structure andthe solvent evaporated therefrom. Inanother embodimentthe resinouscomposition is extruded or cast into a precipitating bath, in which the resins are insoluble and with which the solvent is miscible, and thereafterthe precipitated resinous article dried. V

The nature of the invention will become more apparent by reference to the examples hereinafter set 'forth, wherein the proportions are by weight. It-is to be understoodthat the examples are merely illustrative embodiments of the invention and that the scope of the invention is not restricted thereto. For convenience, the specific synthetic resins and specific blending agents of the examples are designatediby their respective trade names, the identity of which -is.s.et forth in the following table:

TABLE I Trade-name I Medea-11d soldby- "ggg figg Neoprene OG 1 1.01. du Pont de Nemours & chloroprene.

. :.0- I Hycar 012-15- ,B. r. Goodrich o0. 355 55 33 Vlnyon ON... Oarbide -,& Carbon Chemical: {60%;vinyl chloride.

Corp. 40% acrylonitrile.

EXAMPLE 1 15 parts Neoprene CG, 15 parts Hycar OR-15, and 30 parts Vinyon CN were dissolved in a solvent mixture composed of 174 parts acetone and 228 parts dioxane. The resin solution was cast in thin films onto glass plates and the solvent evaporated in air at 50 C. The dried films were stripped from the plates and consisted of 25% Neoprene CG, 25% Hycar OR-15 and 50% Vinyon CN.

EXAMPLE 2 27 parts Neoprene CG, 6 parts Hycar OR,-l5, and 27 parts Vinyon CN were dissolved in a solvent mixture composed of 174 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 45% Neoprene CG, 10% Hycar OR-15 and 45% Vinyon CN.

EXAMPLE 3 28.5 parts Neoprene CG, 28.5 parts Vinyon CN, and 3 parts Hycar OR-15 were dissolved in a solvent mixture composed of 174 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 47.5% Neoprene CG, 47.5% Vinyon CN and Hycar OBI-15.

EXAMPLE 4 21 parts Neoprene CG, 36 parts Vinyon CN, and 3 parts Hycar OR-15 were dissolved in a solvent mixture composed of 174 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 35% Neoprene CG, 60% Vinyon CN and 5% Hycar ORFIS.

EXAMPLE? 5 12 parts Neoprene CG, 42 parts Vinyon CN,

and 6 parts Hycar OR-15 were dissolved in a solvent mixture composed of 174 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 20% Neoprene CG, 70% Vinyon CN and 10% Hycar OR-15.

EXAMPLE 6 36 parts Neoprene CG, 12 parts Vinyon CN, and 12 parts l-Iycar OR,15 pere dissolved in a solvent mixture composed of 174 parts acetone and 228 parts dioxane. Films were prepared from this resin solution by the method set forth in Example 1. The dried films consisted of 60% Neoprene CG, Vinyon CN and 20% Hycar OR-15.

The physical properties of films of several of the foregoing examples are given in the following Table II:

TABLE II Physical properties of film Tear Mois' Example Tensile Elonstrength Film ture Oxygen strength, gation, rams thickvapor translbs. per per; 7 (miss) tragsrlnissq. in. con to s m s on 1 3, 148 77 16 1.44 7 22 6.0 2 2, 892 71 8 1. 60 4. 60 27. 5 3 2, 698 443 618 l. 02 5. 02 50. 8 4 l, 376 556 329 2. 02 l. 42. l 5 4, 497 53 9 1. 60 3. 04 6.

1 Moisture vapor transmissiongrams water per 24 hours per 100 4 Testing methods used in determiniiig values for Table II Tensile strength-Scott Inclined Plane Tensile Strength Tester. A sample 1 inch long by inch wide is used. Tensile strength as used in Table II is given in pounds per square inch based on original cross-section area of the sample.

EZongation.-Determined on same machine and sample as tensile strength.

Tear strength.-Thwing-Albert Research Type Tearing Tester. An initiated tear through a 1 inch length of film is used. Tear strength is recorded in grams per M inch film thickness.

Moisture vapor transmission-Determined by General Foods Method as described in Modern Packaging, November 1942. Transmission given in grams of water passing through an area of 100 square inches of film in 24 hours.

Oxygen transmission.-Determined by method and apparatus described in Paper Trade Journal 118 No. 10, 32 (1944). Transmission recorded as cubic centimeters of gas passing through an area of 100 square inches of film in 24 hours.

No special method of preparing the solution of the synthetic resins and blending agent is necessary. The components can be added either separately or simultaneously to the selected solvent. The mass is preferably agitated until solution is complete. The solution can also be faciltiated and hastened by the application of heat.

As shown by the examples, the solution can be extruded and the solvent evaporated therefrom, or the solution can be extruded into a bath which is a precipitating agent for the resins and preferably also is miscible with the solvent of the composition.

The solvents which can be employed in the production of shaped articles from the solution are not restricted to those of the examples. When, for example, an article is to be prepared by the process wherein the solvent is evaporated, any volatile solvent in which all of the resins are soluble can be used. When the article is to be prepared by a method wherein the solution is extruded into a precipitating bath, any solvent in which all the resins are soluble, and which preferably also is miscible with the precipitating bath, can be used. Generally, such solvent is volatile so that, upon drying of the article, the

residual solvent will be evaporated.

In the embodiment of the invention wherein the solution is extruded into a precipitating bath, the latter is a liquid medium, which precipitates the resin from the solution. The precipitating bath is also one which in admixture with the solvent will form a mixture which is a nonsolvent for the resin. Though many liquid substances and solutions can be used as the precipitating bath, water is preferred because of its economy.

The total resin concentration in the solution is not restricted to those set forth in the examples. In general, when the solution is to be processed by a procedure wherein the solvent is evaporated from the shaped article, the total resin (including blending agent) can vary with tion is extruded into a precipitating bath, a solution viscosity of 10 to 25 seconds by the falling ball method is desired (this represents the time required for a ."'st'eel ba1l to fall vertical- 1y through 8- of the resin solution. A solids content' of approximatelyt'o is required to give such aviscosity.

Instead ofblending through the use of solvents, the various latices can be mixed and thereafter coagulat'ed' and subsequentlyheated and/or milled. I

The'films producedby this invention are transparent and can be unvulcanized or vulcanized, as desired. In general, when a vulcanized film is desired, the composition cancontain any filler, reinforcing. pigment. age: resistorsaccelerators, and vulcanizing ingredients which are ordinarily used in vulcanizing rubber or synthetic. rubber. When such a compositions used, the film, after or duringdrying, can be vulcanized in the known manner. By the appropriate selection. or the vul'canizing agents, one or all ofthe vulcanizable constitutents can be vulcanized to itself' or to each other. vulcanization of a specific constituent depends on the" concentration of such ingredient and the use of thevulcanizing agent which will vulcanizeonly; such ingredient.

Various other. substances may be included in the formula, such as softening'agent's, plasticizers, etc., although: in general these may' not be desirable.

Furthermore, anti-blocking materials, such as paraffin, stearamide, natural waxes, synthetic waxes, stearic acid, cetyl acetamide, ethylene bis palmityl amide, dicetyl ether and their homologues, may be incorporated to improve the surface properties.

As is disclosed in Examples 1-5 inclusive, polychloroprene and vinyl chloride-acrylonitrile copolymer containing 40% acrylonitrile are made compatible by a blending agent which consists of butadiene-(45%) acrylonitrile copolymer.

The blending agent is not restricted to such butadiene-acrylonitrile copolymer. In general, 1,3 butadiene-acrylonitrile copolymer containing from 25% to 45% acrylonitrile can be used as the blending agent and it can be used in amounts of from 5% to 25% by weight of the total resins.

The relative proportions of the polychloro- ;prene and the vinyl chloride-acrylonitrile copolymer can vary within limits. In general, the composition can contain 25% to polychloroprene and 70% to 25% vinyl chloride-acrylonitrile copolymer.

Various solvents are disclosed in Examples 1-5 inclusive, but it is to be understood that the invention is not restricted thereto. Any solvent, as hereinbefore described, can be used. In addition to those set forth in the examples, other illustrative solvents for solutions to be processed by the evaporative method are tetrahydrofuran, dioxane, isophorone, higher ketones such as methyl isobutyl ketone, cyclohexanone, etc., a mixture containing 62% acetone and 38% dioxane, and preferably a mixture containing 85% to 75% acetone and 15% to 25% tetrahydrofuran. Methyl ethyl ketone can be substituted for acetone in a somewhat higher proportion than acetone.

The above-mentioned solvents can be used in wet extrusion processes wherein water constitutes the precipitating bath.

Though the invention has been previously described particularly in connection with the production of film, it is to be understood that the invention is not restricted thereto. The solu- S tions also can be used for the preparation ofself-'- sustaining continuous film in the form of con-'- tinuous seamless tubing. Likewise, the solutions hereinbefore described can be used in the production of other shaped structures, suchas filaments,-yarns,fibers, caps, bands,- etc. Additionally, the solutions can be employed as a coating composition for the coating of various base materials, such as paper, fabric, metal foil, regenerated cellulose, polyvinyl alcohol, nylon, zein, ethyl cellulose, cellulose acetate, etc. Still fur-'- ther, the solutions. can be used as a sealing cementfor gasproofseals of resinous sheet materials, as acement for sealing films of polyvinylidene chloride and its copolymers, as a gasketcement', etc.

Self-sustaining film in the form of continuous sheeting or seamless: tubing produced from the components of synthetic resins, herein described, are. characterized by high resistance to moisture vapor penetration and to penetration by. gases. Because of these roperties, a filmof the synthetic resins hereinbefore described is admirably suited foruse in wrapping and packaging of' any product which is desired tobe protected.

Inaddition to the foregoing properties, afilm of; the. synthetic resins hereinbefore' described is transparent, thermoplastic; heat-sealable; resillent, has a. high tensile. strength, has a fair amount of elongation, is printable, containsno substance which will afiect the odor and taste of the product wrapped therein or will migrate from the film into the product wrapped therein, resists exudation of fatty substances, and is highly resistant to puncture, all of which properties render the material particularly suitable for packaging or wrapping of foodstuifs.

Herein and in the claims the proportions are by weight unless otherwise specified.

In the claims, the term consisting essentially of is intended to cover the named ingredients with or without the modifying ingredients herein disclosed.

Since it is obvious that various changes and modifications may be made in the above description without departing from the nature or spirit thereof, this invention is not restricted thereto except as set forth in the appended claims.

We claim:

1. Formed structures consisting essentially of 25%-60% polychloroprene, '70%-25% of a copolymer of 60% vinyl chloride and 40% acrylonitrile and 5%-25% of a synthetic resin blending agent consisting of a rubbery copolymer of 75%-55% of 1,3 butadiene and 25%-45% acrylonitrile whereby said polychloroprene and vinyl chloride-acrylonitrile copolymer being normally incompatible are made compatible.

2. Formed structures as set forth in claim 1 wherein the blending agent consists of a rubbery copolymer of 55% of 1,3 butadiene and 45% acrylonitrile.

3. Self-sustaining transparent film consisting essentially of 25%-60% polychloroprene, 70% 25% of a copolymer of 60% vinyl chloride and 40% acrylonitrile and 5%25% of a synthetic resin blending agent consisting of a rubbery copolymer of 75%-45% of 1,3 butadiene and 25%-45% acrylonitrile whereby said polychloroprene and vinyl chloride-acrylonitrile copolymer being normally incompatible are made compatible.

4. Self-sustaining transparent film consisting essentially of polychloroprene, 50% of a copolymer of 60% vinyl chloride and 40% acrylonitrile, and 25% of a blending agent consisting of a rubbery copolymer of 55% of 1,3 butadiene and 45% acrylonitrile to make said polychloroprene and vinyl chloride-acrylonitrile copolymer compatible.

5. Self-sustaining transparent film consisting essentially of 45 %-4'7.5% polychloroprene, 45 47.5% of a copolymer of 60% vinyl chloride and 40% acrylonitrile, and 10%-5% of a blending agent consisting of a rubbery copolymer of 55% of 1,3 butadiene and 45% acrylonitrile to make said polychloroprene and vinyl chloride-acrylonitrile copolymer compatible.

6. Self-sustaining transparent film consisting essentially of polychloroprene, 60% of a copolymer of 60% vinyl chloride and acrylonitrile, and 5% of a blending agent consisting of a rubbery copolymer of 55% of 1,3 butadiene and acrylonitrile to make said polychloroprene and vinyl chloride-acrylonitrile copolymer compatible.

'7. Self-sustaining transparent film consisting essentially of 20% polychloroprene, 70% of a copolymer of 60% vinyl chloride and 40% acrylonitrile, and 10% of a blending agent consisting of a rubbery copolymer of of 1,3 butadiene and 45% acrylonitrile to make said polychloroprene and vinyl chloride-acrylonitrile copolymer compatible.

8; Self-sustainingtransparent film consisting essentially of polychloroprene, 20% of a copolymer of 60% vinyl chloride and 40% acrylonitrile, and 20% of a blending agent consisting of a rubbery copolymer of 55% of 1,3 butadiene and 45% acrylonitrile to make said polychloroprene and vinyl chloride-acrylonitrile copolymer compatible.

RALPH J. SIGNER. KEITH F. BEAL.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Garvey et al., Ind. and Eng. Cem., 36 March 1944, pp. 209-211. 

1. FORMED STRUCTURES CONSISTING ESSENTIALLY OF 25%-60% POLYCHOLORPRENE, 70%-25% OF A COPOLYMER OF 60% VINYL CHLORIDE AND 40% ACRYLONITRILE AND 5%-25% OF A SYNTHETIC RESIN BLENDING AGENT CONSISTING OF A RUBBERY COPOLYMER OF 75%-55% OF 1,3 BUTADIENE AND 25%-45% ACRYLONITRILE WHEREBY SAID POLYCHLOROPRENE AND VINYL CHLORIDE-ACRYLONITRILE COPOLYMER BEING NORMALLY INCOMPATIBLE ARE MADE COMPATIBLE. 